[llvm] r278944 - [InstCombine] clean up foldICmpOrConstant(); NFCI

[Reid Kleckner via llvm-commits]

+    Constant *NullVal = ConstantInt::getNullValue(P->getType());
+    Value *CmpP = Builder->CreateICmp(Pred, P, NullVal);
+    Value *CmpQ = Builder->CreateICmp(Pred, Q, NullVal);

P and Q might not have equivalent pointer types. We really do need to get
two calls to getNullValue here.

Caused a crash while building Chromium:

On Wed, Aug 17, 2016 at 9:30 AM, Sanjay Patel via llvm-commits <
llvm-commits at lists.llvm.org> wrote:

> Author: spatel
> Date: Wed Aug 17 11:30:43 2016
> New Revision: 278944
>
> URL: http://llvm.org/viewvc/llvm-project?rev=278944&view=rev
> Log:
> [InstCombine] clean up foldICmpOrConstant(); NFCI
>
> 1. Change variable names
> 2. Use local variables to reduce code
> 3. Use ? instead of if/else
> 4. Use the APInt variable instead of 'RHS' so the removal of the FIXME
> code will be direct
>
> Modified:
>     llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
>
> Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/
> Transforms/InstCombine/InstCombineCompares.cpp?rev=
> 278944&r1=278943&r2=278944&view=diff
> ============================================================
> ==================
> --- llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
> (original)
> +++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp Wed Aug
> 17 11:30:43 2016
> @@ -1879,40 +1879,38 @@ Instruction *InstCombiner::foldICmpAndCo
>    return nullptr;
>  }
>
> -Instruction *InstCombiner::foldICmpOrConstant(ICmpInst &ICI, Instruction
> *LHSI,
> -                                              const APInt *RHSV) {
> +/// Fold icmp (or X, Y), C.
> +Instruction *InstCombiner::foldICmpOrConstant(ICmpInst &Cmp, Instruction
> *Or,
> +                                              const APInt *C) {
>    // FIXME: This check restricts all folds under here to scalar types.
> -  ConstantInt *RHS = dyn_cast<ConstantInt>(ICI.getOperand(1));
> +  ConstantInt *RHS = dyn_cast<ConstantInt>(Cmp.getOperand(1));
>    if (!RHS)
>      return nullptr;
>
> -  if (RHS->isOne()) {
> +  ICmpInst::Predicate Pred = Cmp.getPredicate();
> +  if (*C == 1) {
>      // icmp slt signum(V) 1 --> icmp slt V, 1
>      Value *V = nullptr;
> -    if (ICI.getPredicate() == ICmpInst::ICMP_SLT &&
> -        match(LHSI, m_Signum(m_Value(V))))
> +    if (Pred == ICmpInst::ICMP_SLT && match(Or, m_Signum(m_Value(V))))
>        return new ICmpInst(ICmpInst::ICMP_SLT, V,
>                            ConstantInt::get(V->getType(), 1));
>    }
>
> -  if (!ICI.isEquality() || !RHS->isNullValue() || !LHSI->hasOneUse())
> +  if (!Cmp.isEquality() || *C != 0 || !Or->hasOneUse())
>      return nullptr;
>
>    Value *P, *Q;
> -  if (match(LHSI, m_Or(m_PtrToInt(m_Value(P)), m_PtrToInt(m_Value(Q))))) {
> +  if (match(Or, m_Or(m_PtrToInt(m_Value(P)), m_PtrToInt(m_Value(Q))))) {
>      // Simplify icmp eq (or (ptrtoint P), (ptrtoint Q)), 0
>      // -> and (icmp eq P, null), (icmp eq Q, null).
> -    Value *ICIP = Builder->CreateICmp(ICI.getPredicate(), P,
> -                                      Constant::getNullValue(P->
> getType()));
> -    Value *ICIQ = Builder->CreateICmp(ICI.getPredicate(), Q,
> -                                      Constant::getNullValue(Q->
> getType()));
> -    Instruction *Op;
> -    if (ICI.getPredicate() == ICmpInst::ICMP_EQ)
> -      Op = BinaryOperator::CreateAnd(ICIP, ICIQ);
> -    else
> -      Op = BinaryOperator::CreateOr(ICIP, ICIQ);
> -    return Op;
> +    Constant *NullVal = ConstantInt::getNullValue(P->getType());
> +    Value *CmpP = Builder->CreateICmp(Pred, P, NullVal);
> +    Value *CmpQ = Builder->CreateICmp(Pred, Q, NullVal);
> +    auto LogicOpc = Pred == ICmpInst::Predicate::ICMP_EQ ?
> Instruction::And
> +                                                         :
> Instruction::Or;
> +    return BinaryOperator::Create(LogicOpc, CmpP, CmpQ);
>    }
> +
>    return nullptr;
>  }
>
>
>
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